A contact lens is to be worn in a human eye in order to correct vision, and the development of a contact lens material having low double refraction, excellent oxygen permeability and moldability has been advanced. As a raw material for a contact lens, a polycarbonate material is used. Generally, for preparing a polycarbonate resin, a molecular weight control modifier (chain terminator) such as alkyl-substituted phenol is added thereto in order to control the molecular weight. Examples of a molecular weight control modifier (chain terminator) include highly polar substituted phenols having, for example, a hydroxyalkyl group or a carboxyalkyl group, and by using those, properties of a polycarbonate resin can be changed.
In the case of assuming application to a contact lens like the application in the present invention, it goes without saying that surface wettability is important, and for example, in the case of preparing a transparent gel which comprises the polycarbonate resin and the hydrophilic polymer obtained by polymerizing a hydrophilic monomer and has an interpenetrating network structure of the resin and the hydrophilic polymer, it was confirmed that solubility in the hydrophilic monomer is significantly improved. It is clear that by improving solubility, excellent optical performance and mechanical properties as the contact lens can be exhibited. On the other hand, in the case of use as a contact lens, by blending a polycarbonate resin alone or in combination with other resin, surface characteristics such as surface wettability and adhesion can be improved.
For example, in Patent Document 1, a contact lens material which is excellent in transparency and low in double refraction and has oxygen permeability is disclosed. Also, in Patent Document 2, a contact lens to which flexibility is given by forming a transparent gel is disclosed.